The exemplary embodiment relates to localization of a pointing action on a document for providing information associated with a pointer location. It finds particular application in conjunction with images on paper which are minimally altered to enable unique localization by a camera enabled pointer pen and will be described with reference thereto.
Machine readable information in the form of watermarks, barcodes, and the like has been embedded into images on paper for a variety of applications, such as document identification and precise document-internal pointing localization. The code is generally invisible or visually unobstructive and may be decoded by a camera-enabled pointer-pen. For example, presenting the document to the camera permits the user to recover a document identifier encoded in the watermark which can then be used to retrieve the document from a database which is accessed with the identifier. The image itself is not used for retrieval purposes, but only the watermark-embedded code.
The encoded information is used to associate various actions with the pointing gesture, such as displaying touristic information about a monument pointed on a map, ordering a mechanical part from a paper catalog, retrieving the stored translation of a selected piece of text, playing a recorded interpretation from the position indicated by the pointer on a musical partition, or generally any action that can be triggered by using a mouse with a computer screen.
Early work on what is often referred to as “intelligent paper” focused on the use of invisible inks. However, this requires special printing inks to be installed in the printer. More recently, visually unobstructive marks, such as dataglyphs, have been printed with conventional inks in locations of the image associated with information retrieval. However, these marks do modify the visual appearance of the document, and moreover are generally limited to areas of the document, such as text regions, where there is sufficient surrounding white space.